Polyalcohol homopolymers

ABSTRACT

A polyalcohol homopolymer having the formula: ##STR1## wherein n is about 3 to about 10.

FIELD OF THE INVENTION

The present invention relates to polyalcohol homopolymers having theformula: ##STR2## wherein n is about 3 to about 10. These polyalcoholhomopolymers are useful in thin film applications for the packagingindustry.

BACKGROUND OF THE INVENTION

Thin film composites of polyethylene, a copolymer of ethylene propyleneand polyvinyl alcohol have found extensive use in the food packagingindustries for meats, vegetables and fruits. The polyvinyl alcohol ofthese composite films imparts the necessary barrier properties to thecomposite. The polyethylene imparts the necessary physical properties tothe film composite to enable one to have an integral film system. Theethylene/propylene copolymer acts as a binding agent between theethylene and the polyvinyl alcohol.

The present invention teaches the use of a thin film of a polyalcoholhomopolymer for use in the food packaging industry. The use of thepolyalcohol homopolymer eliminates the need for the use of filmcomposites because the polyalcohol homopolymer besides exhibitingexcellent thermal stability and barrier properties also possessesphysical properties which permit the formation of polymeric thin filmhaving sufficient physical integrity. ##STR3## Polyalcohol likepolyvinyl alcohol, are well known useful materials prepared via freeradical polymerization of vinyl acetate followed by hydrolysis topolyvinyl alcohol. Such polyalcohols always contain unreacted acetateresidues. Also, since the alcohol group is attached directly to thebackbone such polymers do not particularly have high thermalstabilizers.

Direct polymerization of alcohol containing monomers, althoughdesirable, is synthetically difficult to achieve. One reason for thissituation is that alcoholic functionalities poison organometalliccatalysts, like Ziegler-Natta (Al, Ti) catalysts.

Copolymers of alpha-olefins (e.g., ethylene and propylene) with specialalcohol monomers, e.g., undecylenyl alcohol, have been reported by Clark[U.S. Pat. No. 3,492,277 (1979)] be pretreating the alcohol withorganoaluminum compounds. However, this patent does not teach or suggestpolyalcohol homopolymers.

SUMMARY OF THE INVENTION

This present invention relates to a process for forming a polyalcoholhomopolymer having the formula: ##STR4## wherein n is about 3 to about10.

The polyalcohol homopolymer of the instant invention are useful as thinfilms for the packaging industries. Additionally, the polyalcoholhomopolymer can be formed by an extrusion process into a flexible bottlefor use in packaging liquid materials.

GENERAL DESCRIPTION OF THE INVENTION

The present invention relates to a process for the synthesis ofpolyalcohol homopolymers which can be used as a thin film in the foodpackaging industry or in the formation of flexible bottles for packagingliquid materials.

The process for synthesizing the polyalcohol homopolymers comprisesdissolving a polyborane homopolymer in a solvent such as tetrahydrofuranto form a polymeric solution; injecting a sodium hydroxide solution intothe polymeric solution at about 25° C.; injecting a hydrogen peroxidesolution into the polymeric solution at about 0° C. to about 25° C.;heating the polymeric solution to a temperature of about 45° C. to about55° C. and maintaining the polymeric solution at about 45° C. to about55° C. for at least about 2 hours to convert the polyborane homopolymerto the polyalcohol homopolymer; cooling the polymeric solution to roomtemperature; and adding an aliphatic hydrocarbon such as hexane to thepolymeric solution to precipitate the polyalcohol homopolymer from thepolymeric solution.

The polyalcohol homopolymers of the instant invention have the formula:##STR5## wherein n is about 3 to about 10, more preferably about 3 toabout 9 and most preferably about 3 to about 8. The number averagemolecular weight of the polyalcohol homopolymers as measured by GPC isabout 10,000 to about 5,000,000, more preferably about 50,000 to about4,000,000, and most preferably about 30,000 to about 3,000,000. Themolecule structure of the unoriented polyalcohol hompolymer is partialcrystallinity which is related to the syndiotactic propagation duringZiegler-Natta polymerization.

The polyborane homopolymers used in the synthesis of the polyalcoholhomopolymers have the formula: ##STR6## wherein n is about 3 to about10, more preferably about 3 to about 9 and most preferably about 3 toabout 8 and R₁ and R₂ are the same or different alkyl or cycloalkylgroups having about 1 to about 10 carbon atoms such as 9-boranecyclo[3,3,1] nonane.

The polyborane homopolymers are formed by a Ziegler-Natta polymerizationof a borane monomer such as B-7-octenyl-9-BBN, B-5-hexenyl-9-BBN orB-4-pentenyl-9-BBN. To the Ziegler-Natta catalyst of TiCl₃.AA, andAl(ET)₂ Cl and toluene under an inert atmosphere such as argon ornitrogen at room temperature is added the borane monomer. The mixture ofZiegler-Natta catalyst and borane monomer is stirred at room temperaturefor at least 2 hours until the mixture becomes viscous. Thepolymerization reaction is terminated by the addition of an aliphaticalcohol. The precipitate of the polyborane homopolymer is washed withadditional aliphatic alcohol and subsequently vacuum dried.

The borane monomers are prepared by reacting under an inert atmosphereat room temperature 1,5-hexadiene, 1,4-pentadiene or 1,7-octadiene witha solution of 9-BBN-THF for at least about 1 hour. The unreacted dieneand solvent are recovered from the reaction solution by reducing thepressure. The formed borane monomer is recovered by distilling atelevated temperature and reduced pressure.

The thin polymeric films of the polyalcohol homoplymer are at least 5 μmmils thick. These polymeric films are casted from n-propanol solutionwhich contains about 5 weight percent of polyalcohol. The polymer filmexhibits high thermal stability. The major decomposition takes placeabove 450° C., which is quite different from polyvinyl alcohol.Polyvinyl alcohol starts to dehydrate at about 170° C. These resultsobviously suggest that the primary alcohol in our polymer is morethermally stable than secondary alcohol in polyvinyl alcohol.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following examples illustrate the present invention, without,however, limiting the same hereto.

EXAMPLE 1 Preparation of Monomer, B-7-Octenyl-9-BBN

A dry 500 ml flask was equipped with a magnetic stirring bar and aconnecting tube leading to a nitrogen source. The flask was thoroughlyflushed with nitrogen before the injection inlet was capped with arubber serum stopple. A slight positive pressure of nitrogen wasmaintained thereafter. The flask was charged via syringe with 60 ml1,7-octadiene. To the stirred diene solution was then added (viasyringe) 200 ml of the 0.5M 9-BBN-THF solution. Sufficient time wasallowed to ensure complete reaction, then the solvent and unreacteddiene were recovered by reducing pressure. B-octenyl-9-BBN monomer (19.4g, 84%) was distilled at 140° C. under 10 m pressure. Spectroscopicevidences by ZR and H'NMR spectra confirmed the expected molecularstructure of monomer. IR: 3,070 cm⁻¹ (C=CH₂ stretching), 2,850-2,925cm⁻¹ (C-H stretching), 1,807 cm⁻¹ (overtone), 1,640 cm⁻¹ (C=Cstretching), 1,440 cm⁻¹ (Ch₂ bending), 1,370 cm⁻¹ (CH₂ wagging), 905cm⁻¹ (CH₂ =CH bending), 720 cm⁻¹ (CH₂ rocking). 'H NMR: ₁ =4.9-5.2 ppm(CH₂ =C terminal), ₂ =5.6-6.2 ppm (-CH=C), ₃ =1.5-1.9 ppm (CH₂),intensity ratio. ₁ : ₂ : ₃ =2:1:26.

EXAMPLE 2 Preparation of Monomer, B-5-Hexenyl-9-BBN

Following the procedure of Example 1, 190 ml (1.6 mole) of 1.5-hexadienewas reacted with 800 ml (0.5M) of 9-BBN/THF solution. The reaction wasaffected with constant stirring at room temperature. After a period of 3hours, excess 1,5-hexadiene and THF solvent were stripped by vacuumpumping at room temperature. Pure B-5-hexenyl-9-BBN (54 g) was obtainedby distillation at 130° C. with low pressure 10 m. The monomer wascharacterized by IR spectrum.

EXAMPLE 3 Preparation of Monomer, B-4-Pentenyl-9-BBN

Following the procedure set forth in Example 1, 20 g of 1,4-pentadiene,together with 0.5M, 150 ml of 9-BBN/THF solution, was added to the flaskunder a nitrogen atmosphere. The mixture was stirred at room temperaturefor overnight. Excess 1,4-pentadiene and THF were removed by highvacuum. The pure 11 g of B-4-pentenyl-9-BBN was distilled from resultantsolution. The molecular structure of monomer was confirmed by means ofIR spectroscopy.

EXAMPLE 4 Preparation of Polyborane, Poly-B-7-Octenyl-9-BBN

In a 500 ml flask 0.5 mmole of TiCl₃.AA, 3 mmole of Al(Et)₂ Cl and 64 mlof toluene were added under argon atmosphere. After sufficient mixing,43 mmole of B-7-octenyl-9-BBN monomer was followed and resulting mixturewas mechanically stirred at room temperature. A high viscous polymergel-like solution was obtained after 3 hours reaction time. Thepolymerization was then terminated and polymer was precipitated byadding 200 ml of isopropanol. The resulting precipitate was collected byfiltration in N₂ atmosphere. Additional washing with isopropanol wascontinued for several times before drying in vacuum for overnight. Theoverall yield in this Example was 92% with the weight average molecularweight above 3 millions by GPC measurement. The molecular structure ofpoly-B-7-octenyl-9-BBN was identified by IR spectrum 2,925-2,850 cm⁻¹(C-H stretching), 1,440 cm⁻¹ (CH₂ bending), 1,370 cm⁻¹ (CH₂ wagging) and720 cm⁻¹ (CH₂ rocking), as well as by "B NMR spectrum resulted fromchemical shift δ=88.5 ppm (relative to BF₃.OEt₂) corresponding totrialkylborane in polymer. The elementary analysis supported the resultand showed the C:H:B atomic ratio of 16:29:1.

EXAMPLE 5 Preparation of Polyborane, Poly-B-5-Hexenyl-9-BBN

Following the procedure of Example 4, 5 g of B-5-hexenyl-9-BBN waspolymerized in the presence of 0.05 g of TiCl₃.AA, 0.26 g of Al(ET)₂ Cland 50 ml of toluene. After a period of approximately 3 hours ofcontinuous stirring of the reaction mixture, 50 ml of isopropanol wasadded to the reaction mixture and the resulting precipitate wasfiltrated and washed with isopropanol in the nitrogen atmosphere. Afterdrying polymer in vacuum overnight, more than 90% yield was obtained.The IR spectrum of resulting polymer was in good agreement with themolecular structure of poly-B-5-hexenyl-9-BBN.

EXAMPLE 6 Preparation of Polyborane, Poly-B-4-Pentenyl-9-BBN

Following the procedure of Example 4, 6.4 g of B-4-pentenyl-9-BBN waspolymerized by Ziegler-Natta catalyst, TiCl₃.AA (0.8 g), Al(ET)₂ Cl of(0.4 g), toluene (50 ml). After stirring the solution for overnight, 50ml of isopropanol was added to stop reaction. The resulting precipitatewas collected by filtration and washed with isopropanol, resulting in 3g powder.

EXAMPLE 7 Preparation of Poly-octene-8-ol

In the inert atmosphere, 6 g of polyoctene-7-9-BBN was dissolved into400 ml THF solution. A 5.3 ml (6N) NaOH solution was injected into thereactor, followed by dropwising 10.7 ml, 33% H₂ O₂ at 0° C. for over 15minutes. The resulting mixture was then heated up to 50° C. for 3 hoursto complete the reaction. After cooling down to room temperature, thepolymer was then precipitated from solution by adding 200 ml hexane.Further purification was carried out by redissolving polymer inton-propanol and reprecipitating polymer from petroleum ether. Theresultant wet polymer was adhesive to glass and metal. After dryingpolymer in vacuum oven for 2 days a glassy-like poly-octene-8-ol wasobtained.

Infrared spectrum of resulting polymer, summarized in Table 1, confirmedthe molecular structure of poly-octen-8-ol.

                  TABLE 1                                                         ______________________________________                                        Characteristics of the Infrared                                               Spectrum of Poly-octenol                                                      Frequency   Relative                                                          (cm-1)      Intensity  Assignment                                             ______________________________________                                        3,300       Strong     O--H Stretching                                        2,900       Strong     C--H Stretching                                        2,840       Strong     C--H Stretching                                        1,440       Strong     C--H and O--H Bendng                                   1,370       Medium     CH.sub.2 Wagging                                       1,050       Strong     C--O Stretching                                          720       Medium     CH.sub.2 Rocking                                       ______________________________________                                    

The polymer was further characterized by 'H NMR spectrum with chemicalshift δ=4.4 ppm for proton in hydroxyl group of polyocten-8-ol.Elementary analysis results (Table 2) was in good agreement with thetheoretical value, and confirmed that quantitatively oxidation ofpolyborane can be achieved as those in organoboranes.

                  TABLE 2                                                         ______________________________________                                        Elemental Analysis                                                            Results of Polyoctenol                                                        (C.sub.8 H.sub.16 O).sub.x                                                             C       H       O     B      Total (%)                               ______________________________________                                        Theoretical                                                                            75.0    12.5    12.5  0      100                                     Values                                                                        Experimental                                                                           74.33   13.03   12.61 0.049  100.02                                  Values                                                                        ______________________________________                                    

EXAMPLE 8 Preparation of Polyhexene-5-ol

Following the procedure of Example 7, 5 g of poly-5-hexenyl-9-BBN in 400ml of THF was oxidized by 6N, 5 ml of NaOh and 33%, 10 ml of H₂ O₂solution. After stirring at 50° C. for 3 hours, the reaction mixture wascooled down to room temperature. The resulting polymer was precipitatedfrom the solution by adding 300 ml of hexane, then was collected byfiltration. After washing with methanol, the polymer was dried in vacuumfor overnight. The molecular structure of polyhexene-5-ol wascharacterized by IR intense modes, .sub.νO-H 3,300 cm⁻¹ and .sub.νC-O1,050 cm⁻¹.

EXAMPLE 9 Thermal Properties of Polyocten-8-ol

The thermogravimetric analysis results of the polymer powder exhibitedgood thermal stability. In inert atmosphere (e.g. Ar), less than 3%weight loss was observed at 300° C. The decomposition took place about400° C. and rapidly increased over 500° C. The good thermal stability ofpolyoctenyl alcohol is quite different from that of polyvinyl alcoholwhich is dehydrated at about 170° C. and further decomposed above 250°C. The results obviously suggest that the primary alcohol in polyoctenylalcohol is more stable than secondary alcohol in polyvinyl alcohol.Moreover, the space group between hydroxyl group and polymer backbone isimportant to delay the decomposition, such as non-catalyzed reversealdol condensation which happen in polyvinyl alcohol.

In the presence of air, the polymer was stable up to 280° C. withoutexperiencing significant weight loss. Rapid oxidation took place near480° C. resulting in a large weight loss. At 487° C. the weight loss wasnear complete, most of the polymer was decomposed in air with verylittle inorganic impurities left. This was in good agreement with theelementary analysis results, the sum of carbon, hydrogen and oxygen near100%, in Example 7.

EXAMPLE 10 Molecular Structure of Polyocten-8-ol

Polyocten-8-ol was glassy with partial crystallinity at roomtemperature. The morphology of polyocten-8-ol is completely differentfrom that of polyoctene which is a viscous gum at room temperature, hasnot been obtained crystallinity even at low temperature. The x-raypattern of unoriented polyocten-8-ol is principally characterized by twostrong reflections at Brogg angle 2 θ=18° and 20° corresponding tospacing (d') of 4.8 Å, and 4.4 Å, and one weak reflection at 2 θ=9.4°corresponding to spacing (d') of 9.4 Å. Two reflections at 'd=4.8 Å and4.4 Å represent the spacing between parallel side chains, analogous tothe reflection maximum on x-ray patterns of amorphous n-paraffins andpolyolefins with long side chains, such as polydecene. The d' values ofcomb-like polymers are quite insensitive to the length of the side chainand fall between 4 and 5 Å. In contrast, the spacing between polymerchains (d") grows with the increased values of spacing group. The valueof d"can be used to judge the conformation of side chain. The differencebetween d"=9.4 Å for polyoctene-8-ol and (d" (estimated)=12 Å) forpolyoctene is significant. It may be relative to strong intermolecularinteraction resulting from hydrogen bonding.

EXAMPLE 11 The Viscosity of Polyocten-8-ol Solution in n-Propanol

A solution of polyocten-8-ol was prepared in n-propanol at aconcentration of 0.5 weight percent. The viscosity of this 0.5 weightpercent solution was about 9.1 cp at 1.3 sec⁻¹ and at 25° C. Afterconcentrating the solution by blowing nitrogen through the solution, theviscosity of resulting 3 weight percent solution was almost about 170 cpat 1.3 sec⁻¹.

What is claimed is:
 1. A polyalcohol homopolymer having the formula:##STR7## wherein n is about 3 to about 10, wherein said polyalcoholhomopolymer has a partial crystalline molecule structure of asyndiotactic configuration and a number average molecular weight of atleast 30,000 and said polyalcohol homopolymer has high thermal stabilitywith a major decomposition temperature above 450° C., said polyalcoholhomopolymer being formed by reacting a polyborane homopolymer with aNaOH/H₂ O₂ solution of about 0° to about 25° C.
 2. A polymeric filmhaving a film thickness of at least 5 μm mils, wherein said polymericfilm comprises a polyalcohol homopolymer having the formula: ##STR8##wherein n is about 3 to about 10, wherein said polyalcohol homopolymerhas a partial crystalline molecule structure of a syndiotacticconfiguration and a number average molecular weight of at least 30,000and said polyalcohol homopolymer has high thermal stability with a majordecomposition temperature above 450° C., said polyalcohol homopolymerbeing formed by reacting a polyborane homopolymer with a NaOH/H₂ O₂solution of about 0° to about 25° C.